In ‘The Performers’, opening this week at the Longacre Theater, Winkler stars as an aging male porn star. Photo:

That fountain of hair is still there, though it’s gone from dark to silver, and the nose has gotten larger with time. But there’s no mistaking Henry Winkler, a.k.a. Arthur Herbert Fonzarelli, a.k.a.The Fonz.

At least until he says his first line: “Whose a- -hole do I have to fist to get a drink around here?”

Clearly, “Happy Days” aren’t here again. Instead, we’re at “The Performers,” David West Read’s raunchy but shockingly sweet comedy about the adult-entertainment industry. Opening this week at Broadway’s Longacre Theater, it features Winkler as Chuck Wood, the hardest working guy — pun intended — in the business.

From the moment he takes the stage, the audience is rooting for him. Turns out, Chuck Wood’s biggest organ is his heart.

And that, Winkler says, is why he took the role.

“The [bawdy] language makes my own socks go up and down,” the 67-year-old says. “Eventually, though, you forget the language and care about the character.”

At the Regency Hotel the other day, the short (5-foot-6) native New Yorker kept pulling the cuffs of his blue cashmere sweater over his hands to warm them; living in California for the last 40 years may have thinned his blood.

Even after “Happy Days” ended — after a decade of shows that gave us The Fonz, Ron Howard’s Richie and the immortal phrase, “jumping the shark,” which involved Winkler and a pair of water skis — Winkler never stopped moving.

He produced, he directed, he shilled (for reverse mortgages — really, Henry?) and turned out a series of children’s books about his youthful alter ego: dyslexic Hank Zipzer, The World’s Greatest Underachiever. That last, coupled with talks he’s given to British schoolchildren, recently won him an honorary OBE.

So he’s no underachiever. He was even too busy to accept his OBE from Prince Charles! The only thing royal he had time for lately was TV’s “Royal Pains.” He was shooting a show in New York when someone invited him to a reading of “The Performers.” Winkler went, he read — and he laughed, even though the language made him blush.

Not that he’s a complete stranger to kinkiness. When asked about the weirdest place he’d ever had sex, Winkler recalls a high-brow night on the town: “It was the back seat of a BMW in the parking structure of the Los Angeles Philharmonic. It was satisfying and cultural at the same time.”

Winkler did violate one of his own longtime showbiz rules in taking the part. He didn’t consult his spouse.

“My wife said, ‘You did this without talking to me? You decided not only to move our life to New York but to do this and to say that?’

“I said, ‘Stacey, I don’t know what to tell you. I’m on this journey, and I have no control over this. I’m on the train, and I’m going!’ ”

Minutes later, Stacey Winkler, his impeccably groomed wife of 34 years, walks into the Regency dining room with their 3-year-old granddaughter.

Stacey, is that true?

She rolls her eyes. “Yes,” she says. “It’s the first time he didn’t give me the script to read!”

This isn’t Winkler’s first time on Broadway. Maybe you caught him a decade ago, in Neil Simon’s “The Dinner Party,” or even “Forty-two Seconds from Broadway,” which ran, well, about 42 seconds on Broadway (one night).

He’s thrilled to be back on the boards, and waxes long and sweet about the cast and the entire creative team, most of them three decades younger than he is.

“I’ve never lived in a world without Henry Winkler,” says Evan Cabnet, the show’s 34-year-old director. He says his mom once bought him a Fonzie action figure: “Press him, and his thumb shoots out!”

Cheyenne Jackson, who plays Chuck’s rival — a hunky side of beef named Mandrew — says Winkler’s “like a father figure” to the rest of the cast.

Nevertheless, Jackson says, he finds himself playing mentor.

“He’ll ask me, ‘Cheyenne, what does that mean?’ ” Jackson says, declining specifics. “And I think, I can’t believe I’m having this conversation with Henry Winkler!”